Modern aircraft (and older types too) have pretty high tire pressures. As the aircraft sits on deck, the tire area touching the tarmac will be flat on the surface...and us model geeks like that look, it looks "real". This, does not look "real"! :
I typically achieve the look by running a fresh sheet of sandpaper under the tire as it sits on a flat surface, but the risk of breaking something is high there. Yesterday I decided to try a method that a buddy of mine shared...sitting the model on a hot iron. Sounds more risky, man!
Well, the idea, is to set the model on a